How do I challenge a candidate? To challenge a candidate, you must file a challenge petition in court no later than 5:00 p.m. on the 10th business day after the candidate Nomination Petition submission deadline. The challenge petition must specifically list the reasons for the challenge. If signatures on a candidate’s Nomination Petitions are being challenged, the challenge must specifically identify the Nomination Petition page and line number for each signature being challenged, and the reasons why the signatures are being challenged. For more information see A.R.S. §16-351 and A.R.S. §16-351.01. Any candidate in any election can be challenged by any registered voter.